EP 1 798 572 A discloses a traffic alert and collision avoidance system (TCAS) system on a host aircraft that includes a processor, a transmitter, and a receiver. The transmitter generates an interrogation signal based upon surveillance alerts, such as approaching aircraft and threat potentials, produced by surveillance radar. The surveillance radar transmits TCAS transmitter interrogation signals and receives replies at a receiving device. A target aircraft includes a surveillance system that receives the interrogation signal at a transmitter receiving device and, when interrogated, generates a standard transponder reply signal via a transmitter.
The second generation of the TCAS system (the so-called TCAS II system), which is used in the majority of commercial aviation aircraft offers the pilot direct, vocalized instructions to avoid danger, known as a resolution advisory. TCAS II systems coordinate their resolution advisories before issuing commands to the pilots, so that if one aircraft is instructed to descend, the other will typically be told to climb—maximizing the separation between the two aircraft.
However, the ability of the host aircraft to perform an avoidance maneuver is limited by the designed aircraft flight envelope. This is especially true for avoidance maneuvers undertaken in the Collision Avoidance phase of an encounter. Further, an avoidance maneuver utilizing excessive vertical or horizontal velocities may increase the risk for induced collisions with aircraft flying at neighboring flight levels—above or below. Therefore a reduction of the recognition time for the aircraft pilots flying at neighboring flight levels may be the result. However, aborting or reverting an avoidance maneuver utilizing excessive vertical or horizontal velocities requires more time, thereby making it more difficult to prevent an induced collision.
Hence, there is a need to provide an improved method for an aircraft for handling potential collisions in air traffic, which is in particular improved in view of preventing impact of detect and avoid induced collision conflicts, especially in RVSM (Reduced Vertical Separation Minimum) airspace.